Colorectal cancer (CRC) is a significant and preventable disease, yet CRC screening rates remain low. Incorporating patient's preferences into CRC screening decisions has been advocated by the United States Preventive Services Task Force, and others, as a mechanism for increasing screening adherence. However the impact of such a preference-tailored strategy on important outcomes, including screening adherence and cost, is unknown. The broad hypothesis of the proposed study is that helping eligible patients clarify their CRC screening preferences will lead to increased adherence. The framework conceptualizes that preference clarification will increase the patient's knowledge and awareness of the factors that are important to him or her in getting screened for CRC. Patients will be better prepared to participate in an informed decision making process with their provider. Improving informed decision making will lead to reduced decisional conflict, a greater intention to get screened and, eventually, to better adherence with screening. The specific aims are: 1) To test the effectiveness of a preference-tailored (PT) vs. standard information (SI) intervention for increasing primary care patient's CRC screening adherence in a randomized controlled trial at two locations; 2) To assess the impact of the intervention on informed decision making, knowledge and attitudes toward screening, decisional outcomes, and intention to get screened; and 3) To conduct a cost effectiveness analysis of the PT intervention for increasing CRC screening. We will conduct a randomized controlled trial of the PT vs. SI decision tool at two locations; Henry Ford Health System in Detroit, Michigan and the San Francisco Community Health Network, affilated with the University of San Francisco. The intervention is a web-based decision tool that has been developed by the P.I. working with the Center for Health Communications Research at the University of Michigan. 275 eligible participants (age 50-79, not current with CRC screening, no personal or family history of CRC, scheduled primary care visit) will be enrolled at each study site and randomized to the PT or SI intervention at the time of log-in to the web-site. Particpants will be encouraged to come to the clinic location prior to their appointment to view the web-site. The option to view the web-site from home will be offered for those who have the adequate Internet capabilities, experience with computers, and the ability to view the site no more than 24 hours prior to their primary care appointment. Preference information will be collected through the computer program. Participants will be called approximately 3 days after their primary care visit to collect informed decision making measures. Adherence to screening will be collected from electronic and paper medical charts 12 months after their visit. Hypotheses related to each aim will be tested using multi-level modeling to control for between-provider and site effects. The overall hypothesis is that patients in the PT group will have higher rates of CRC screening adherence at the 12 month follow-up point. Cost effectiveness analysis will determine whether a preference-based screening strategy is cost effective. Public Health Relevance: Colorectal cancer (CRC) screening is a significant and preventable disease, yet screening rates remain low. Incorporating patient's preferences into CRC screening decisions has been advocated by the United States Preventive Services Task Force, and others. This application outlines a randomized controlled trial at two sites to test the effectiveness of a web-based, preference-tailored CRC screening decision tool for increasing screening adherence. The results will have direct relevance for improving informed decision making for CRC screening which can be applied to the multitude of preference-sensitive healthcare decisions faced by patients in the U.S.